MERKEL CELL-CARCINOMA - REPORT OF 10 CASES WITH EMPHASIS ON CLINICAL COURSE, TREATMENT, AND IN-VITRO DRUG-SENSITIVITY

Background: Merkel cell carcinoma (MCC) is an uncommon primary neuroen docrine skin tumor most often seen in the elderly. The clinical course varies. Treatment is controversial and few data on drug sensitivity a re available. Objective: We evaluated the clinical course and treatmen t of 10 MCC patients and determined MCC chemosensitivity. Methods: Cli nical records as well as laboratory and histopathologic data from 10 p atients with MCC treated in our department were examined. Chemosensiti vity to various chemotherapeutic agents and interferons of MCC cells f rom four patients was determined in a soft agar clonogenic assay. Resu lts: MCC behaved as an aggressive tumor with early and frequent local relapses (4 of 10 patients at a 2.2-month average), regional (4 of 10 patients at 2.5 months), and distant metastases (5 of 10 patients 9.6 months after excision of the primary tumor). In all but one patient, r egional metastases preceded distant ones. Metastatic spread was associ ated with an average survival of 21 months from the initial diagnosis. Long-term survival (53+ and 65+ months) was observed in two women. Wi de excision of the primary tumor, alone or combined with adjuvant chem otherapy and radiotherapy, was the most effective treatment. In advanc ed disease, chemotherapy and radiotherapy were not able to induce long -term remission. In vitro assays for MCC drug sensitivity revealed cis platin; doxorubicin, and vindesine to be the most active. Conclusion: MCC has a poor prognosis in advanced stages; therefore the primary tum or should be aggressively treated. The in vitro clonogenic assay may h elp to identify the chemosensitivity profile of MCC and to optimize ch emotherapy protocols.